Mac OS X users, Thanks to help from Bruce Ravel and Matt Newville, I have updated ifeffit and Demeter-devel in Macports to fix a number of problems reported. To update from your current version type the following: sudo port selfupdate sudo port upgrade outdated To install from scratch after installing Macports [1]: sudo port selfupdate sudo port install demeter-devel When done, your should see the following ports installed: $ port installed ifeffit p5.16-ifeffit demeter-devel The following ports are currently installed: demeter-devel @0.9.20pre10_0 (active) ifeffit @1.2.13_0+gcc48 (active) p5.16-ifeffit @2_0 (active) Please reply to the list (NOT to me directly) about how this works for you. Cheers! Frank [1] https://www.macports.org/install.php